Google uses it's own web crawlers and data centers to index billions of web pages. Start Page is designed to return results from a single source, google, excluding all other search engines. A metasearch means to search through multiple sources, in this case multiple search engines.
Using google for this example:
If you were to type
autoruns in the search box at google, the results would be links to all over the web. But, if you were to restrict the search to BleepingComputer, type
autoruns site:bleepingcomputer.com in the search box, all of the resulting links would lead to BleepingComputer. You are telling google to show you the results from a single web site and to exclude resutls from any other web site.
A "single source search"(
Start Page) is pretty much the opposite of a "metasearch"(
DuckDuckGo, Ixquick). It would be extremely difficult to have it both ways at the same time.
DuckDuckGo not only shows the results from other search engines, but also pulls info from sources other than search engines as well as using it's own web crawler.
Edit:
If you use Firefox, you should try Didier's suggestion. It could very well be the solution to your dilemma.